Browsing by Subject "antimicrobial susceptibility testing"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Direct antimicrobial susceptibility testing of positive blood cultures: A comparison of the accelerate Pheno™ and VITEK® 2 systems
    (Elsevier, 2019) Schneider, Jack G.; Wood, James B.; Smith, Nathan W.; Emery, Christopher L.; Davis, Thomas E.; Manaloor, John J.; Bocian, Brittany; Schmitt, Bryan H.; Medicine, School of Medicine
    Objectives To compare the performance and time-to-result (TTR) for antimicrobial susceptibility testing (AST) of positive blood cultures (PBC) using the Accelerate Pheno™ system (AXDX) and both a direct VITEK® 2 card inoculation workflow (DV2) and traditional FDA-approved VITEK® 2 workflow using subcultured isolates (V2). Methods Patient samples with monomicrobial Gram-negative rod bacteremia were tested on AXDX and DV2 in tandem, and compared to V2 AST results. Categorical agreement (CA) errors were adjudicated using broth microdilution. Instrumentation times and AST TTR were compared. Results AXDX and DV2 had a CA of 91.5% and 97.4%, respectively, compared to V2. Post-adjudication, AXDX, DV2, and V2 had CA of 94.7%, 95.7% and 96.5%, respectively. Instrument run times were 6.6 h, 9.4 h, and 9.2 h, and AST TTR were 8.9 h, 12.9 h and 35.5 h, respectively. Conclusions AXDX and DV2 AST is fast and reliable, which may have significant antimicrobial stewardship implications.
  • Thumbnail Image
    Item
    Multicenter Evaluation of the Etest Gradient Diffusion Method for Ceftolozane-Tazobactam Susceptibility Testing of Enterobacteriaceae and Pseudomonas aeruginosa
    (American Society for Microbiology, 2018-08-27) Bailey, Adam L.; Armstrong, Tom; Dwivedi, Hari-Prakash; Denys, Gerald A.; Hindler, Janet; Campeau, Shelley; Traczewski, Maria; Humphries, Romney; Burnham, Carey-Ann D.
    Ceftolozane-tazobactam (C/T) is a novel beta-lactam–beta-lactamase inhibitor combination antibiotic approved by the U.S. Food and Drug Administration in 2014 for the treatment of complicated intra-abdominal infections (in combination with metronidazole) and complicated urinary tract infections., Ceftolozane-tazobactam (C/T) is a novel beta-lactam–beta-lactamase inhibitor combination antibiotic approved by the U.S. Food and Drug Administration in 2014 for the treatment of complicated intra-abdominal infections (in combination with metronidazole) and complicated urinary tract infections. In this study, we evaluated the performance of the C/T Etest, a gradient diffusion method. C/T Etest was compared to broth microdilution (BMD) for 51 Enterobacteriaceae challenge isolates and 39 Pseudomonas aeruginosa challenge isolates at three clinical sites. Essential agreement (EA) between the methods ranged from 47 to 49/51 (92.2 to 96.1%) for the Enterobacteriaceae, and categorical agreement (CA) ranged from 49 to 51/51 (96.1 to 100.0%). EA and CA for P. aeruginosa were 100% at all sites. The C/T Etest was also compared to BMD for susceptibility testing on 966 clinical isolates (793 Enterobacteriaceae, including 167 Klebsiella pneumoniae and 159 Escherichia coli isolates, in addition to 173 P. aeruginosa isolates) collected at four clinical sites. EA between Etest and BMD was 96.9% for Enterobacteriaceae isolates and 98.8% for P. aeruginosa isolates. Within the Enterobacteriaceae, isolates from each species examined had >96% CA. For the clinical isolates, no very major errors were identified but two major errors were found (one for K. pneumoniae and one for Providencia rettgeri). By BMD, 47.0% of Enterobacteriaceae and 46.2% of P. aeruginosa challenge strains were nonsusceptible to C/T by CLSI breakpoint criteria; 8.2% of clinical Enterobacteriaceae isolates and 12.1% of clinical P. aeruginosa isolates were nonsusceptible to C/T by CLSI breakpoint criteria. In conclusion, Etest is accurate and reproducible for C/T susceptibility testing of Enterobacteriaceae and P. aeruginosa.